SANFORD — Vowing never to relent, the Rev. Jesse Jackson, other civil-rights leaders and the parents of slain teen Trayvon Martin demanded that city commissioners do their part to ensure shooter George Zimmerman is arrested.

"The whole world is watching Sanford," Jackson said. "The whole world is watching Florida today."

A line of speakers, including U.S. Rep. Corrine Brown, D-Jacksonville, and U.S. Rep. Sheila Jackson Lee, D-Texas, echoed Jackson's message. The Rev. Al Sharpton delivered a petition he said had 2 million signatures on it demanding Zimmerman's arrest.

Sharpton told Sanford leaders that the city is poised to be saddled with a reputation for trampling the civil rights of black people if it did not take action.

Zimmerman, Neighborhood Watch coordinator at the Retreat at Twin Lakes town-house community, told police he acted in self-defense Feb. 26 when he killed the Miami Gardens 17-year-old. Florida law allows people to use deadly force if they think they are being threatened with serious harm or death.

Trayvon, who was visiting family, was walking back from 7-Eleven wearing a hoodie when he encountered Zimmerman, who called police to report him as a suspicious person.

Zimmerman told Sanford officers that Trayvon punched him, knocked him to the ground and banged his head on the pavement as Zimmerman cried out for help. Trayvon's family says 911 tapes show the boy was the one yelling for help.

Zimmerman has not been arrested, provoking nationwide protests, the appointment of a special prosecutor and even a comment from President Barack Obama. The U.S. Department of Justice and the FBI also are investigating.

Like the other speakers, Trayvon's parents asked commissioners to make things right.

"We're not asking for an eye for an eye. We're asking for justice, justice, justice," his father, Tracy Martin, said, pointing his finger for emphasis.

Trayvon's mother, more soft-spoken, said her heart is broken.

"I know I cannot bring my baby back," Sybrina Fulton said. "But I'm sure going to make changes so that this doesn't happen to another family."

An overflow crowd cheered and waved "Justice for Trayvon" signs at Fort Mellon Park on the Sanford lakefront as the parents' images appeared on two large screens.

During a rally at the park after the meeting, Martin family attorney Natalie Jackson praised the crowd for remaining nonviolent. On Saturday, the New Black Panther Party offered a $10,000 reward for Zimmerman's "capture."

"If you are not here to be in peace, you are not welcome," Jackson said.

Tracy Martin said many of the faces at the rally reminded him of Trayvon.

"They took a son from me, but they gave me a million kids," he said.

The Rev. Jamal Bryant of Baltimore, who has been preaching in Central Florida about the killing, called the case "a critical moment in history."

"The hip-hop generation is taking over the civil-rights movement," Bryant said.

Before the meeting, Sharpton, Jackson, Trayvon's parents and Baltimore Ravens linebacker Ray Lewis led a march from Centennial Park in Sanford to the civic center.

"It's justice that should be blind, not the Sanford police," read a sign one protester carried.

Anjail Madyun of Orlando wore a pink T-shirt that read, "It's not a black or white thing. It's a right or wrong thing."

Madyun, 40, said that "until we get beyond black and white, we'll have to come to events like this. Mothers will always be crying. Fathers will always be burying their sons."

Before the march began, the sounds of Martin Luther King Jr.'s "I Have a Dream" speech spilled from Centennial Park on Park Avenue in Sanford. His voice came from the speakers of Jamal Bell's red bicycle with a trailer that he converted to a rolling sound system.

"It's 2012. This shouldn't still be going on," said Bell, 27, a Seminole State College student. "We need to stand up for what is right."

Andy Anderson, a 67-year-old white man wearing a T-shirt that said "I am Trayvon Martin," said he marched for civil rights in the 1960s and felt the need to do it again.

As the meeting was starting, Sanford City Commissioner Mark McCarty was taken to a hospital with chest pains, which he has suffered in the past. McCarty was the commissioner who made a motion of no confidence in the Sanford police chief last week. Chief Bill Lee stepped aside temporarily.

The mother of slain teen Trayvon Martin wants to trademark her son's name in the slogans, "I am Trayvon" and "Justice for Trayvon," according to two petitions filed with the United States Patent and Trademark Office.